Cow dung is the latest culprit found to be causing arsenic poisoning in unsuspecting villagers in West Bengal, India.

During the last century people living in China, Nepal, India and Bangladesh were encouraged to use well water rather than surface water.  Whilst reducing the number of casualties from bacterial diseases, it was soon discovered that the well water is contaminated by arsenic leaching from rock.  Sickness through drinking the well water and rice, and other crops, irrigated with contaminated water has been widely reported.  Dipankar Chakraborti and colleagues from Jadavpur University, India, have now discovered another related route through which people in West Bengal are exposed to arsenic.

Chakraborti explains that in this region cow dung, from cows fed contaminated rice straw, is dried in the sun and used as fuel in domestic ovens.   He found that when the cow dung cakes are burnt arsenic is released into the air, which is then inhaled.  

Jose Centeno, an expert in medical geology at the US Armed Forces Institute of Pathology in Washington, DC, said the findings are important as they describe yet another previously unknown source of arsenic exposure in this region.

The exposure is magnified because the ovens and kitchens are not ventilated, said Chakraborti.  He explained that woman and children in the region are the worst affected because they spend an average of seven hours a day next to ovens.  Inhalation of arsenic leads to respiratory problems such as persistent coughs and reduced lung capacity, said Chakraborti.

Centeno believes that a concerted effort is needed to prevent further communities being exposed to arsenic.  He said that geoscientists are currently 'trying to determine the source rocks from which arsenic is being leached' and to determine what caused the arsenic to be mobilised from the rock.  

Nina Athey-Pollard